The IMDB lists this film as Isolar's only movie. It's doubtful that it's Bowie's Isolar as that is a private management company, not really a full fledged production unit.

If his company had produced it, he most certainly would have gotten an 'executive producer' credit. You don't even have to be directly involved with the movie to get that (Bowie actually has been an E.P. for two foreign made movies).